a. Field of Invention
This invention relates to novel indole derivatives, and to the processes for their preparation and use.
Notwithstanding the advances made during the last four decades in the development of agents for the treatment of inflammatory conditions and/or for analgesic purposes in conditions which require relief from pain in a mammal, there still remains a need for effective agents without the side effects associated with the therapeutic agents presently used for these purposes.
More specifically, this invention relates to tricyclic acetic acid derivatives in which the tricyclic portion thereof is characterized by having an indole portion fused to a pyrano ring. Still more specifically, the compounds of this invention are characterized as derivatives of the following tricyclic acetic acid system: ##STR1## 1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid in which the carbons at the 1-, 5-, 6-, 7-, and 8-positions are further substituted.
The indole derivatives of this invention have been found to exhibit useful pharmacodynamic properties without eliciting undesirable side effects. Notable attributes of this effect are anti-inflammatory and/or analgesic activities.
b. Prior Art
The closest prior art to the present invention is:
Demerson et al, U.S. Pat. No. 3,939,178. Demerson et al disclosed 1,3,4,9-tetrahydropyrano[3,4-b]indoles and 1,3,4,9-tetrahydrothio-pyrano[3,4-b]indoles having analgesic and anti-inflammatory activity but not with the substituents of the present invention. McKittrick et al, Canadian Pat. Application No. 530,253, filed Feb. 20, 1987. Hughes et al, U.S. Ser. No. 876,522, filed June 19, 1986, now abandoned. Related U.S. Pat. Nos. are U.S. Pat. Nos. 3,974,179; 3,843,681 and U.S. Ser. No. 838,510, filed Mar. 11, 1986, now U.S. Pat. No. 4,670,462.